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lidar_tools

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Tools to process airborne and satellite LiDAR point clouds.

Warning! This package is under active development and may change rapidly!

Datasets Supported

Output Products

  • Digital Surface Models: IDW interpolation based gridding of height values for first and only returns.
  • Digital Terrain Models: IDW interpolation based gridding of height values for ground returns (Classification==2). We do not perform ground classification ourselves, input point clouds need to have ground returns labelled for terrain models generation. An additional gap-filled product using IDW interpolation with a 9 x 9 kernel can also be produced which is useful in reducing data gaps in areas with dense canopy or buildings.
  • Surface Intensity: IDW interpolation based gridding of surface intensity values for first and only returns.

UW Campus preview Sample of standard products created with lidar_tools rasterize utility for University of Washington Campus AOI, using publicly-available USGS 3DEP lidar point clouds (WA_KingCounty_2021_B21)

Quickstart

lidar_tools is a collection of CLI scripts to process LiDAR data. It should be installed into a stand-alone environment to ensure that scripts execute as intended. We recommend using pixi to install a locked software environment.

We recommend using pixi package manager to install a locked software environment for executing code in this repository.

Pixi can be installed following instructions from here. For Linux and Mac OSX machines, pixi can be installed from the terminal by running the below command:

curl -fsSL https://pixi.sh/install.sh | sh
git clone https://github.com/uw-cryo/lidar_tools.git
cd lidar_tools
pixi install --frozen

Example workflow

Run our example workflow to create DSM, DTM without interpolation, DTM with interpolation, and LiDAR Intensity for 3DEP data over a part of University of Washington Campus in Seattle, WA!

# NOTE: takes ~5 min to run
pixi run example

CLI Commands

Once installed, you can run processing scripts from a terminal:

export PIXI_FROZEN=true # NOTE: set this to always use locked environment
pixi shell # NOTE: 'exit' deactivates the environment
lidar-tools --help            # all commands
lidar-tools rasterize --help  # options for one command
Command What it does
search Search the lidar catalog: which collections cover an AOI, at what quality level and acquisition dates, with what declared CRS/datum/geoid, EPT availability, AOI overlap, and the uncovered fraction.
prepare Stage discovery metadata for an AOI into site_manifest.yaml: pinned WESM records, EPT name resolution, TESM-vs-links tile reconciliation, staged-LAZ cache layout.
rasterize Create DSM, DTM (with and without gap filling) and/or intensity rasters from 3DEP EPT or local LAS/LAZ.
rasterize-projects Run rasterize once per survey into per-project subdirectories sharing one target grid, so the outputs are co-registered.
merge Merge a batch's per-project products into per-product VRT composites (priority order, no resampling), normalizing intensity to a common range.
preview Write a one-page preview figure (shaded relief, scale bar, processing footer) for a run or for every project in a batch.
fetch-reports Stage each project's vendor QA/QC, survey and mapping reports plus the USGS vertical-accuracy checkpoints next to its products.
report-metrics Extract standardized metrics (acquisition period, tested vertical/horizontal accuracy, point density) from those reports into one record per project, with per-number source evidence.

Multi-project workflow

For an AOI covered by more than one 3DEP survey, the commands chain:

lidar-tools search aoi.geojson                       # what covers this AOI?
lidar-tools prepare aoi.geojson batch/               # pin the metadata once
lidar-tools rasterize-projects aoi.geojson \
    AZ_PimaCo_1_2021,AZ_PimaCo_2_2021 \
    batch/ --resolution 1                            # co-registered per-project products
lidar-tools merge batch/                             # per-product composites
lidar-tools preview batch/                           # QA figures
lidar-tools fetch-reports batch/                     # vendor reports
lidar-tools report-metrics batch/                    # standardized accuracy table

Projects are listed in priority order: the first one wins where they overlap. See docs/vendor_reports.md for the report staging and metric extraction details (repo-only: docs/ is not shipped in the built package).

Development

Use a developement environment (including pytest, ruff, mypy etc)

export PIXI_FROZEN=true # Disable this if you're changing dependency versions
pixi shell -e dev

Or run the test sweet

pixi run test

Run linting and formatting

pixi run lint
pixi run typecheck

Packaging

To create a conda package that can be installed into any conda environment:

pixi build

This will output a .conda file named something like lidar_tools-0.1.0-pyhbf21a9e_0.conda

To actually install the package it needs to put in a conda "registry" or "channel" like conda-forge. For now we are using a public channel at https://prefix.dev/channels for development:

conda install -c https://repo.prefix.dev/uw-cryo lidar_tools

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Tools to process airborne and satellite LiDAR point clouds

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